Question: If $x \star y = xy+2x-y$ and $x \triangleright y = x-3y$, find $0 \star (-1 \triangleright 2)$.
Answer: First, find $-1 \triangleright 2$ $ -1 \triangleright 2 = -1-(3)(2)$ $ \hphantom{-1 \triangleright 2} = -7$ Now, find $0 \star -7$ $ 0 \star -7 = (2)(0)-(-7)$ $ \hphantom{0 \star -7} = 7$.